1. Field of Invention
The present invention relates to systems for forecasting and communicating meteorological information, and in particular, to systems for producing multi-period probability of precipitation (POP) forecasts and disseminating the same through communications channels including, but not limited to the Internet, wireless devices, and broadcast systems.
2. Description of the Prior Art
The present invention was developed primarily in response to the need for enhanced weather information based on probability forecasts, a need recognized by members of The American Meteorological Society (AMS) in a 2002 Statement.
According to the AMS, weather forecasts have improved dramatically over the past two decades. In fact, forecasts produced by operational forecasters using meteorological observation data and forecasts produced by numerical models have become more accurate for nearly all weather elements and for most time and space scales of interest. Those forecasts contribute important information to decision makers and are valuable to a multitude of users, including the general public, the military, aircraft operators, businesses, and emergency managers, to name a few.
Progress has also been observed in developing accurate probability forecasts, which have a significant economic benefit because a sizable portion of the U.S. economy is weather sensitive. That progress has been important because POP forecasts (the percentage chance that a measurable amount of precipitation (at least 0.01 inches of rain or ice or 0.1 inches of snow) will fall at a specific location during a specific time period) are well accepted by many end users, including the general public.
Probability forecasts also have several benefits over categorical forecasts. One benefit is that they contain more information: the uncertainty in the forecast is expressed as part of the forecast. Thus, the end user is made aware of the uncertainty in the forecast and can use that additional information in making decisions. However, not all end users understand the information provided by probability forecasts or the meteorological event being represented by the forecasts. In its simplest terms, most people understand what is meant by the probability of an event occurring, such as the probability of obtaining “heads” when flipping a coin. What is significantly less intuitive to end users of POP forecasts is what is meant by a forecast that says “there is a 30% POP for State College, Pa., tomorrow.” Often, that forecast is interpreted ostensibly as meaning that it will rain over 30% of the State College, Pa., area tomorrow or there is a 30% chance it will rain somewhere in the immediate region tomorrow. Other combinations of those and other interpretations are also likely. Thus, while quantitative precipitation forecasts have become more accurate, have advantages over categorical forecasts, are generally accepted by the general public, and are relatively simple in terms of the information provided, they are, by their very nature, rather complex.
To simplify the complexity, according to the AMS, a POP forecast should provide a probability of any desired amount, say 0.5 to 1.0 inches of precipitation, for any desired time interval. Until the present invention, POP forecasts have been issued for periods of 24, 12 or six hours, starting at a preset, fixed time, such as 7 am, and this time would not change dynamically. Those intervals are too long to provide sufficient detail as to when precipitation might occur and when it is most likely to occur. Shorter intervals, such as three hours, would be significantly better in terms of accuracy. The problem with shorter intervals, however, is that simply dividing the longer period into shorter intervals can result in inaccurate or even meaningless forecasts. For example, given a probability of precipitation for a 6-hour period (POP-6) of 60%, simply dividing the POP-6 hours into two three-hour intervals and calculating POP-3 values based on the data for those hours may not accurately represent the probability of forecast for the two intervals. In fact, as the time interval for the POP gets shorter, eventually it becomes physically impossible to have enough precipitation fall to qualify under the definition of a measurable amount. A more robust computational method is needed to generate accurate probability of precipitation values for periods shorter than 6 hours.
Another problem with current systems is that once the preset starting time for a period has passed (i.e., the starting time for the POP for the two 12-hour periods beginning at 7 am-7 pm), the POP time periods would not move with the clock. That means that at, for example, 9 am, the POP forecast available would be for the 7 am-7 pm period (or possibly the remainder of that period) and for 7 pm-7 am, rather than 9 am-9 pm and 9 pm-9 am time periods. Further, once 0.01 inch of precipitation has fallen, the probability of precipitation would by definition be 100% for the period. Thus, a probability of precipitation that does not reset every hour during precipitation would tell the user nothing about the future weather, and would therefore be of no value. In addition, a probability of precipitation that is less than 100% and does not reset during precipitation, would be inconsistent with the weather that has occurred and the definition of POP, and therefore inaccurate and confusing. Accordingly, probability of precipitation forecasts that reset to the present time would also be better in terms of accuracy and usefulness.
U.S. Pat. No. 6,424,917, for example, discloses a system and method for spatial synoptic classification using “sliding seed days” as model inputs rather than fixed time periods. That method is disclosed as being advantageous in terms of forecasting synoptic conditions.
To also simplify the complexity of probability forecasts, according to the AMS, there should be new ways for displaying and communicating the probabilistic information compared to those presently available. The National Weather Service (NWS), operating under the auspices of the National Oceanic and Atmospheric Administration (NOAA), has recently been experimenting with communicating probability forecast information to various interested parties. Called a graphical forecast, the NWS chose a graphical (map) approach for displaying information on its web site that may be accessed over the Internet. The information available for displaying is generated and maintained in NOAA's National Digital Forecast Database, and includes POP-12 data (the percentage chance that a measurable amount of precipitation (at least 0.01 inches of rain or ice or 0.1 inches of snow) will fall at a specific location during a 12-hour time period). However, even on the NWS's “Experimental Products” web site, they do not offer any POP forecasts for less than 6 hours nor do they offer any POP forecasts that are not for pre-set, non-rolling time periods.
Commercial companies also use their web pages for providing weather-related information, but other communication channels have also been used, such as electronic mail over the Internet and facsimile, as in the case of “E-Weather,” which is provided to users by SkyBit, Inc. The “E-Weather” data may be in the form of a table array (3-hour time period increments along the top of the table and weather parameters (e.g., temperature, humidity, POP-6, etc.) along the left edge of the table). It is significant to note that even in this table array, although most data is presented in 3-hour increments, the POP forecasts are presented in 6 hour increments. U.S. Pat. No. 6,654,689 discloses methods of providing meteorological data (storm warnings) that include using a server connected to the Internet (or another network) for providing web-based text and images to a client's computer, uploading the same information directly to a third party's web site, sending the data via a pager or phone, and communicating the data and other information through broadcast systems (television or satellite). As discussed in U.S. Pat. No. 6,498,987, advances in computer connectivity technology available in most locations have allowed advances in communicating weather information to end users via the Internet by using web pages maintained on servers connected to the Internet and operated by various communications companies, such as local television and radio companies.
Before any information may be communicated to an end user, however, the appropriate probability forecast information must be determined. Systems and methods for generating the information are well known in the art. U.S. Patent Application Serial No. 2002/0114517A1, for example, discloses a short-term storm predictor system whereby meteorological image data from satellites or other sources is computer-processed to generate a 10- to 120-minute severe thunderstorm forecast (the raw data may be available, for example, from NOAA's NEXRAD network of radar systems). The results are communicated by a graphical representation of the event centered on the graph. Each pixel represents a location within a region and can be assessed a numerical value that represents, for example, the rate of precipitation. U.S. Pat. No. 6,128,578 also analyzes time-series changes in real-time radar images to forecast precipitation, the output being a graphical display having contoured and colored probability rings superimposed over a spatial region.
Although many features of the present invention are described in the prior art, none of the prior art patents are directed to a system specifically for providing location-specific, time-sliding (less than six-hour) probability of precipitation forecasts via the Internet. Moreover, the prior art do not contain any suggestion or motivation to calculate probability of precipitation values for time periods less than six hours or on a rolling time basis. There remains, therefore, the need for such a system to provide more accurate forecasts that may be used by decision makers planning activities that are weather sensitive.